Partially reduced oxygen species (PROS), produced by reduced heme bound Aβ peptides, can cause oxidative stress and synaptic damage in the brain, which is one of the key pathological features of Alzheimer's disease. In situoxidation of the heme center by a physiological redox agent like Cytochrome c (Cyt c) can significantly suppress neurotoxic PROS formation. Thus, Cyt c can potentially act as a neuroprotective agent against AD.